JP5410832B2 - Power generation system and auxiliary unit - Google Patents

Description

  The present invention relates to a power generation system that generates electric energy and thermal energy through a fuel cell, and an auxiliary unit.

A fuel cell is a power generator that generates electrical energy and thermal energy through a chemical reaction between hydrogen and oxygen. Usually, in order to extract electric energy from chemical energy, energy loss increases because it passes through energy conversion such as thermal energy (water vapor) and kinetic energy (turbine). On the other hand, since the fuel cell directly converts chemical energy into electric energy, power generation efficiency can be increased. Also, it emits almost no air pollutants such as carbon dioxide (CO ₂ ), nitrogen oxide (NOx), sulfur oxide (SOx), and particulate matter (PM). It is expected to replace the existing generator as an electrical energy generator.

  In addition to supplying the electrical energy generated by the fuel cell to the electrical equipment, hot water heated by heat exchange with the thermal energy generated during power generation is stored in a hot water storage tank, and the stored hot water is used for shower hot water etc. A cogeneration system is known (for example, Patent Document 1).

  In a cogeneration system using a fuel cell, the environmental impact caused by power generation can be kept low, and the economic effect on users, such as utilizing the thermal energy generated during power generation for hot water supply, is also regarded as important. For this reason, a highly heat-retaining container is used for the hot water storage tank for storing warm hot water, and the power generation operation is controlled to stop in a situation where the hot water becomes hot and sufficient heat recovery cannot be performed. Since leaving the generated thermal energy as it is may cause problems in terms of safety, the above mechanism considers safety as well as economy.

JP 2004-053120 A

  As described above, the conventional cogeneration system is configured to stop power generation when the water temperature in the hot water storage tank rises to a predetermined hot water storage upper limit value. Therefore, once the water temperature in the hot water tank reaches the upper limit of hot water storage, the hot water in the hot water tank is used for hot water supply, and power generation is only performed temporarily when the water temperature drops due to the addition of low-temperature tap water. It had been.

  However, when a disaster such as an earthquake occurs, a long-term “power outage” may occur. In addition, it is fully possible that a “water outage” and a “power outage” will occur at the same time during a disaster. Therefore, it is desirable to supply power by power generation of the fuel cell to the minimum necessary electronic devices even when a power failure occurs. However, in the above-described technique, power generation is stopped when the water temperature of the hot water storage tank becomes high, so that it is not possible to perform continuous power supply.

  In view of such a problem, the present invention provides a power generation system and an auxiliary unit that can continuously generate power during an emergency such as a power outage, and can improve user convenience and ensure safety. It is aimed.

In order to solve the above problems, a power generation system including a power generation unit and an auxiliary unit connected to the power generation unit includes a hot water storage tank in which the power generation unit stores hot water and heat, and electrical energy and thermal energy through a chemical reaction. A heat exchanger that recovers heat energy generated by heat exchange with hot water in the hot water tank, and when the hot water in the hot water tank is lower than a predetermined temperature, the fuel cell is driven to generate power, and the predetermined temperature A power generation control unit that stops power generation by the fuel cell when the above is reached, the auxiliary unit dissipates the hot water passed from the hot water tank, and the hot water in the hot water tank is hot or cold And an auxiliary control unit that circulates hot water in the hot water storage tank through the circulation channel when the temperature is high and stops the circulation when the temperature is low.

In addition, in order to solve the above problems, the thermal energy generated by the heat exchange between the hot water storage tank for storing hot water and the hot water, the fuel cell for generating electric energy and thermal energy through a chemical reaction, and the hot water in the hot water storage tank. It is connected to a power generation unit including a heat exchanger to be recovered and a power generation control unit that drives the fuel cell to generate power when the hot water in the hot water tank is lower than a predetermined temperature, and stops power generation by the fuel cell when the temperature exceeds the predetermined temperature. The auxiliary unit determines whether the hot water passed from the hot water tank is dissipated and whether the hot water in the hot water tank is hot or cold. And an auxiliary control unit that circulates and stops the circulation when the temperature is low.

  In a power generation unit, a fuel cell chemically reacts a fuel such as hydrogen with an oxidant such as oxygen to generate electric energy and heat energy, and the generated heat energy is replaced with hot water and accumulated and kept in a hot water tank. . However, when the water temperature in the hot water tank rises to a predetermined hot water storage upper limit value, the power generation is stopped, and thereafter, the power generation by the fuel cell is temporarily executed only when the hot water is taken out or the water temperature decreases with time. In the present invention, hot water in a hot water tank is forcibly radiated and circulated in an emergency such as a power failure, and the water temperature in the hot water tank is not allowed to reach the hot water storage upper limit value, thereby enabling continuous power generation. In the present invention, when the water temperature of the hot water storage tank is sufficiently low, low temperature hot water is not circulated unnecessarily, and only at high temperatures, thereby avoiding a decrease in heat dissipation efficiency and reducing power consumption. it can.

  The auxiliary unit may further include a power failure detection unit that detects a power failure, and the auxiliary control unit may circulate the hot water when the power failure detection unit detects the power failure and the hot water in the hot water tank is hot.

  When the power failure detection unit detects a power failure and the water temperature in the hot water tank is above a predetermined threshold, the water pump actively dissipates and circulates the hot water in the hot water tank so that the water temperature in the hot water tank does not reach the upper limit value of the hot water storage. It is possible to continuously generate power during a power outage that requires electricity.

  The auxiliary control unit may circulate hot water for a predetermined time after the power failure detection unit detects the power failure regardless of the water temperature of the hot water tank.

  Even if the water pump stops the circulation of hot water, power generation is continued unless the hot water in the hot water tank reaches the hot water storage upper limit. However, under certain conditions, such as when power generation is not performed for a long time, the temperature in the hot water tank becomes uniform, the temperature of the hot water on the vertical upper end side of the hot water tank decreases, and the hot water on the vertical lower end side of the hot water tank The temperature may approach the hot water storage upper limit. In this case, if power generation is performed without performing circulation, the water temperature on the vertical lower end side of the hot water tank easily reaches the hot water storage upper limit value, and power generation may stop. In the present invention, when the power failure detection unit detects a power failure, it is possible to continuously generate power by forcibly circulating hot water for a predetermined time.

  The circulation channel receives hot water from the hot water tank through a hot water heater that supplies hot water from the hot water tank, and the auxiliary unit further includes a heating detector that detects whether the heat treatment is performed in the hot water heater. The control unit may determine that the water temperature of the hot water tank is low when the heating detector detects that the heat treatment is being performed.

  When the water temperature in the hot water tank is not sufficiently high, the hot water in the hot water tank may be heated in the water heater. If the auxiliary unit thoroughly performs heat dissipation even when the water temperature of the hot water storage tank is low, the opposite processes of heating and heat dissipation are executed in parallel, resulting in poor heat dissipation efficiency. In the present invention, it is determined whether the water temperature of the hot water tank is high or low according to the presence or absence of the heat treatment, and the heat dissipation efficiency is ensured not to circulate the low-temperature hot water when the heat treatment is performed, but to circulate only at a high temperature. Can be avoided and power consumption can be reduced.

  The component corresponding to the technical idea in the auxiliary unit described above and the description thereof can be applied to the power generation system.

  As described above, according to the present invention, it is possible to continuously generate power during an emergency such as a power failure, thereby improving user convenience and ensuring safety.

1 is a block diagram illustrating a schematic configuration of a power generation system according to a first embodiment. It is the block diagram which showed the schematic structure of the electric power generation system in 2nd Embodiment. It is a state transition diagram showing state transition in the power generation method. It is explanatory drawing which showed operation | movement of each valve and pump in a normal state. It is a schematic diagram for demonstrating the flow of the hot water in a normal state. It is explanatory drawing which showed operation | movement of each valve and pump in a power failure state. It is a schematic diagram for demonstrating the flow of the hot water in a power failure state. It is explanatory drawing which showed operation | movement of each valve and pump in a water-stop state. It is a schematic diagram for demonstrating the flow of the hot water in a water cutoff state. It is explanatory drawing which showed the operation | movement of each valve and pump in a power failure and a water stop state. It is a schematic diagram for demonstrating the flow of the hot water in a power failure and a water cutoff state. It is explanatory drawing which showed transition of each valve and pump opening and closing in each process at the time of a power failure. It is explanatory drawing which showed the transition of each valve and the opening and closing of a pump in each process at the time of power recovery. It is explanatory drawing which showed the transition of each valve and the opening and closing of a pump in each process at the time of a water stop. It is explanatory drawing which showed the transition of each valve and the opening and closing of a pump in each process at the time of condensate. It is explanatory drawing which showed the transition of each valve and the opening and closing of a pump in each process at the time of the water stop during a power failure. It is explanatory drawing which showed the transition of each valve and the opening and closing of each pump in each process at the time of condensing during a power failure. It is explanatory drawing which showed the transition of the opening and closing of each valve and pump in each process at the time of the power failure during a water outage. It is explanatory drawing which showed the transition of the opening and closing of each valve and pump in each process at the time of power recovery during a power failure.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(First embodiment: power generation system 100)
FIG. 1 is a block diagram illustrating a schematic configuration of the power generation system 100. The power generation system 100 mainly includes a power generation unit 110 and an auxiliary unit 120. In the power generation unit 110, electric energy and thermal energy are generated through the fuel cell, and at least the thermal energy is retained as hot water. The auxiliary unit 120 performs an auxiliary process regarding the hot water circulation in the power generation system 100.

(Power generation unit 110)
As shown in FIG. 1, the power generation unit 110 includes a hot water storage tank 150, a power generation radiator 152, a fuel cell 154, a heat exchanger 156, a water heater 158, and a power generation control unit 160. Thermal energy generated by itself is stored in hot water storage tank 150 as sensible heat of hot water.

  The hot water storage tank 150 is formed of a container having high heat insulation performance capable of storing a predetermined volume (for example, 100 liters) of hot water, and is full when the power generation unit 110 is in operation. However, since the hot hot water subjected to heat exchange is returned to one end of the hot water tank 150 (for example, the vertical upper end side 170) as described later, the water temperature increases toward the upper end in the hot water tank 150. A temperature difference occurs above and below 150.

  The power generator radiator 152 cools the hot water remaining in the vertical lower end side 172 of the hot water storage tank 150. Such hot water cooling methods include a liquid cooling method using liquid as a heat exchange medium and an air cooling method using air.

  The fuel cell 154 converts hot water cooled by the power generator radiator 152 into, for example, water vapor, and reforms the fuel such as city gas, liquefied petroleum gas (LPG), and kerosene mixed with the obtained water vapor into hydrogen. Then, electric energy and thermal energy are generated through a chemical reaction between the reformed hydrogen and an oxidizing agent such as oxygen. The fuel cell 154 includes a polymer electrolyte fuel cell (PEFC), a phosphoric acid fuel cell (PAFC), a molten carbonate fuel cell (MCFC), which have different electrolytes and operating temperatures. : Molten Carbonate Fuel Cell), Solid Oxide Fuel Cell (SOFC), Alkaline Fuel Cell (AFC), Direct Fuel Cell (DFC), etc. The

  The heat exchanger 156 performs heat exchange between the fuel cell 154 and hot water on the vertical lower end side 172 of the hot water storage tank 150 cooled by the power generator radiator 152 to recover thermal energy generated by power generation. Further, the hot water heated by heat recovery is returned to the vertical upper end side 170 of the hot water tank 150.

  A hot water heater (backup hot water heater) 158 is connected to the vertical upper end 170 of the hot water tank 150 and the tap water receiving port 174 of the hot water tank 150, and a water temperature desired by the user set in the hot water operating device (not shown). Hot water in the hot water storage tank 150 and tap water are mixed and hot water is supplied from the hot water supply valve 176 so that the temperature becomes (for example, arbitrarily set within 32 ° C. to 60 ° C.). The hot water heater 158 includes a heat treatment unit 178. When the hot water on the vertical upper end side 170 of the hot water storage tank 150 has not reached the set water temperature, the hot water supply 158 corresponds to the hot water in the hot water storage tank 150 until the desired water temperature is reached. Further heat treatment is performed.

  The power generation control unit 160 is composed of a semiconductor integrated circuit including a central processing unit (CPU) and a signal processing unit (DSP: Digital Signal Processor), and manages and controls the entire power generation unit 110 using a predetermined program. The power generation control unit 160 executes power generation by the fuel cell 154 when the measured value of the temperature sensor 180 that measures the temperature of the hot water in the hot water storage tank 150 is lower than a predetermined temperature. In addition, when the measured value of the water pressure sensor 186 that measures the pressure of the hot water in the hot water tank 150 is less than a predetermined pressure, the power generation control unit 160 recognizes that a water break has occurred, and shifts to a water break abnormal state for safety and generates power. Restrict so that it cannot be done.

  The main purpose of the power generation unit 110 is to generate hot water used by a user by utilizing thermal energy generated by power generation, and to keep the hot water in the hot water storage tank 150 while keeping it warm. Therefore, when the water temperature of the hot water storage tank 150 rises to a predetermined hot water storage upper limit (for example, 65 ° C.), the power generation control unit 160 cannot sufficiently recover the thermal energy generated by the power generation, so that the power generation by the fuel cell 154 stops. It is configured. The water temperature of the hot water storage tank 150 can be derived by directly measuring the water temperature of the vertical lower end side 172 of the hot water storage tank 150, or the temperature measured upstream or downstream of the power generator radiator 152 is a temperature corresponding to the hot water storage upper limit value. It can also be derived indirectly by converting to.

  Then, when the user executes hot water supply and tap water is received through the water receiving port 174 instead of the hot water discharged by the hot water supply, and the water temperature decreases as a whole, or only when the water temperature decreases over time, power generation is performed. Unit 110 temporarily resumes power generation by fuel cell 154 until the temperature of hot water tank 150 reaches the hot water storage upper limit.

  In addition, power for starting or maintaining operation of the power generation unit 110 and an auxiliary unit 120 described later at the time of a power failure is supplied by a backup power source that is stored in advance by the power generation unit 110 or a commercial power source. This backup power source may be provided in either the power generation unit 110 or the auxiliary unit 120.

(Auxiliary unit 120)
As shown in FIG. 1, the auxiliary unit 120 includes a circulation channel 222, a power failure detection unit 224, a water pump 226, a circulation valve 228, and an auxiliary control unit 230. Hot water in the hot water tank 150 is circulated using the circulation flow path 222.

  The circulation flow path 222 is configured by a hollow tube using a heat dissipation material such as metal, for example, and flows and radiates hot water in the hot water storage tank 150. As described above, in the power generation unit 110, power generation is stopped when the water temperature in the hot water storage tank 150 rises to a predetermined hot water storage upper limit value, and thereafter, the fuel cell 154 is temporarily used only when hot water is supplied through the water heater 158 or when the water temperature is lowered. Power generation is performed. This is due to the fact that hot water storage, particularly hot water insulation, is prioritized over power generation.

  However, in the event of an emergency such as a power outage, an alternative means for commercial power is required, so continuous power generation by the power generation unit 110 is desired. Therefore, in the auxiliary unit 120, in the event of an emergency such as a power failure, the hot water stored in the hot water storage tank 150 is actively radiated and circulated through the circulation passage 222 so that the water temperature in the hot water storage tank 150 does not reach the hot water storage upper limit value. This allows the power generation unit 110 to continuously generate power.

  The power failure detection unit 224 monitors the voltage of the commercial power supply and detects a power failure.

The water supply pump 226 supplies hot water radiated through the circulation flow path 222 to the vertical lower end side 172 of the hot water storage tank 150 at a predetermined water pressure (for example, 2.0 kgf / cm ² ). That is, the water pump 226 has a function of circulating the hot water staying on the vertical upper end side 170 of the hot water storage tank 150 to the vertical lower end side 172 of the hot water storage tank 150 after passing the heat through the circulation flow path 222 to dissipate heat. Here, the water supply pump 226 supplies water at a pressure equal to or higher than a predetermined pressure that is a threshold used by the power generation control unit 160 to detect a water failure abnormality.

  Based on the control of the water pump control unit 234, which will be described later, the water pump 226 does not operate during normal times (no power outage) when the hot water cooling circulation of the hot water storage tank 150 is not necessary, and cools the hot water that has been kept warm. However, it operates during an emergency when it is desired to execute power generation, for example, when a power failure is detected by the power failure detection unit 224. The water pump 226 functions as a simple pipe (flow path) when not operating. The operation of the water supply pump 226 in an emergency may be performed continuously or intermittently as necessary. When the power failure detection unit 224 detects a power failure, the water pump 226 actively dissipates and circulates the hot water in the hot water storage tank 150 so that the water temperature in the hot water storage tank 150 does not reach the hot water storage upper limit value. It is possible to continuously generate power during power outages that require power.

  Further, a flow path for drawing tap water from the water supply 182 is connected to the circulation flow path 222. The water supply pump 226 supplies hot water radiated by the circulation flow path 222 and tap water from the water supply 182 to the hot water storage tank 150. The hot water storage tank 150 is provided with a tap water receiving port 174 for replenishing hot water supplied by the hot water heater 158. Here, the hot water radiated in the circulation flow path 222 and the tap water are combined to effectively use the existing water receiving port 174 without altering the power generation unit 110, and the hot water and the tap water are used as the water receiving port. Water can be sent.

  The circulation valve 228 opens and closes the circulation flow path 222 according to control by a circulation valve control unit 236 described later. Circulation valve 228 functions as a means for preventing hot water in hot water storage tank 150 from flowing into circulation flow path 222.

  The auxiliary control unit 230 is composed of a semiconductor integrated circuit including a central processing unit (CPU) and a signal processing unit (DSP), manages the entire auxiliary unit 120 using a predetermined program, and mainly the status of each part in the auxiliary unit 120. The determination and control of each valve and pump are performed, and the function of executing circulation control of hot water between the hot water tank 150 and the circulation flow path 222 is performed.

  In the present embodiment, the auxiliary control unit 230 includes a valve control unit 232 and a water pump control unit 234.

  The valve control unit 232 controls each valve included in the auxiliary unit 120. In the present embodiment, the valve control unit 232 also functions as a circulation valve control unit 236 and a drain valve control unit 238 described later.

  The circulation valve control unit 236 opens and closes the circulation valve 228. Specifically, the circulation valve control unit 236 closes the circulation valve 228 when the power failure detection unit 224 does not detect a power failure (hereinafter simply referred to as normal time), and the power failure detection unit 224 detects a power failure ( Hereinafter, the circulation valve 228 is opened at the time of a power failure) to enable circulation of hot water.

  The circulation valve control unit 236 can prevent the hot water stored in the hot water storage tank 150 from flowing into the circulation flow path 222 by closing the circulation valve 228 at the normal time. In this way, it is possible to avoid a situation in which the heat retaining function of the hot water storage tank 150 is lowered due to mixing of the radiated hot water in the circulation passage 222 with the hot water in the hot water storage tank 150.

  The water pump control unit 234 controls driving or stopping of the water pump 226 in cooperation with the circulation valve control unit 236 of the valve control unit 232. The water pump control unit 234 does not drive the water pump 226 at normal time, but drives it at the time of power failure to execute circulation.

  Here, the auxiliary controller 230 determines whether the hot water in the hot water tank 150 is hot or cold, and controls the circulation valve 228 and the water pump 226 according to the water temperature of the hot water tank 150. . That is, it is desirable not to circulate low-temperature hot water when the water temperature in the hot water tank 150 is sufficiently low (below the predetermined temperature) and to circulate only when the water temperature is high (above the predetermined temperature). Even so, when the water temperature in the hot water storage tank 150 is low, the circulation valve 228 is closed and the water pump 226 is not driven. As a result, it is possible to avoid a reduction in heat dissipation efficiency and to reduce power consumption. Further, the level of the water temperature in the hot water tank 150 may be obtained by using the measurement result of the hot water temperature sensor 180, separately, a sensor for measuring the temperature of the side wall of the hot water tank 150, or heating of the water heater 158 as will be described later. A sensor (heating detector 240) that detects the operation state of the process can also be used.

  By using the auxiliary unit 120 described above, the power generation unit 110 can be used efficiently in consideration of economic efficiency during normal times, and power supply by continuing power generation is more important than economic efficiency when a power failure occurs during a disaster. Then, since the power generation unit 110 can be utilized, necessary electrical devices such as lighting, a mobile phone, a television, and a refrigerator can continue to be used. In addition, even if a mechanical security guard that constantly monitors the indoors is installed in the facility or home, it can continue to be energized, so that it can protect itself from secondary damage such as theft and illegal intrusion aimed at disasters. It becomes possible.

(Second embodiment: power generation system 200)
In the first embodiment, the conceptual embodiment of the present invention has been described through the power generation unit 110 and the auxiliary unit 120. In the second embodiment, a detailed configuration of the power generation system 200 and its operation will be described through the auxiliary unit 220 more specifically showing the auxiliary unit 120 in the first embodiment.

  FIG. 2 is a block diagram illustrating a schematic configuration of the power generation system 200. The power generation system 200 includes a power generation unit 110 and an auxiliary unit 220. The power generation unit 110 includes a hot water storage tank 150, a power generation radiator 152, a fuel cell 154, a heat exchanger 156, a water heater 158, and a power generation control unit 160, as shown in FIG. The

  The auxiliary unit 220 includes a circulation channel 222, a power failure detection unit 224, a water supply pump 226, a circulation valve 228, an auxiliary control unit 230, a heating detector 240, a hot water supply valve 242, and a circulation radiator 246. The circulation intake valve 248, the drainage valve 250, the drainage check valve 252, the circulation check valve 254, the water storage tank 256, the drainage drain valve 258, the drainage valve 260, the temperature detector 262, and the drainage drainage. A valve 264, a flow rate sensor 266, a drainage check valve 268, a drainage and storage intake valve 270, a tap water receiving valve 272, a tap water receiving pressure reducing valve 274, a water pressure sensor 276, a water cutoff detector 278, and a tap water A water check valve 284, a water supply check valve 286, and a water supply valve 288 are configured. The circulation flow path 222 includes a circulation radiator 246 and a water storage tank 256 as a part of its configuration.

  Here, the circulation channel 222, the power failure detection unit 224, the water supply pump 226, the circulation valve 228, and the auxiliary control unit 230 that have already been described as the components in the first embodiment have substantially the same functions. Therefore, redundant description is omitted, and here, other components of the auxiliary unit 220 having different configurations will be mainly described. In addition, as described in the first embodiment, it is desirable that the circulation flow path 222 is connected to the vertical upper end side 170 of the hot water storage tank 150 to directly circulate hot water that has become hot, as in this embodiment. When the hot water storage tank 150 is not provided with a port for taking out hot water, the hot water in the hot water storage tank 150 can be circulated through the hot water heater 158 by connecting to the hot water heater 158. In this way, it is possible to improve the convenience of the user and ensure safety without altering the existing power generation unit 110.

(Auxiliary unit 220)
The heat detector 240 is composed of a thermostat or the like, is installed in the water heater 158 of the power generation unit 110, and determines whether or not the heat treatment is performed by the heat treatment unit 178 of the water heater 158. Note that the operation state of the heat treatment may be detected by being electrically connected to the water heater 158 and inputting an operation signal.

  As described above, in this embodiment, the circulation flow path 222 is connected to the hot water heater 158, and the circulation flow path 222 receives the hot water in the hot water storage tank 150 through the hot water heater 158. Therefore, the circulation valve control unit 236 and the water supply pump control unit 234 control the circulation valve 228 and the water supply pump 226 according to the presence / absence of the heating process of the heating detector 240. That is, the heat detector 240 determines whether the water temperature in the hot water storage tank 150 is high or low based on the presence or absence of heat treatment, and the circulation valve control unit 236 and the water pump control unit 234 detect that the heat treatment is being performed. It determines with the tank 150 being low temperature.

  Similar to the auxiliary unit 120 in the first embodiment, the auxiliary unit 220 in the second embodiment actively dissipates and circulates hot water in the hot water tank 150 in an emergency such as a power failure, and the water temperature of the hot water tank 150 is set to the upper limit of hot water storage. By not reaching the value, the power generation unit 110 can continuously generate power. However, when the water temperature in the hot water tank 150 is not sufficiently high, the hot water in the hot water tank 150 may be heated in the hot water heater 158 in some cases.

  If the auxiliary unit 220 thoroughly performs heat dissipation even when the water temperature of the hot water storage tank 150 is low, the opposite processes of heating and heat dissipation are executed in parallel, resulting in poor heat dissipation efficiency. Further, wasteful power consumption due to the heat treatment of the water heater 158 occurs. Further, when the temperature of the hot water storage tank 150 is low, power generation is continued by the power generation unit 110 itself without circulating hot water. Here, the level of the water temperature in the hot water tank 150 is determined based on the presence or absence of the heat treatment, and the heat dissipation efficiency is ensured by avoiding unnecessary circulation of the low-temperature hot water when the heat treatment is being performed and circulating only at high temperatures. To reduce power consumption.

  At this time, if the position of the circulation valve 228 for stopping the circulation of hot water is set upstream of the hot water supply valve 242, hot water supply cannot be performed as soon as the circulation is stopped. Moreover, if the position of the circulation valve 228 is a circulation path after the heat-dissipated hot water and tap water are mixed, the supply of tap water is interrupted as soon as the circulation is stopped. 110 will be stopped. Accordingly, in order to prevent such a problem, the position of the circulation valve 228 is simply changed from the branch point from the water heater 158 to the hot water supply valve 242 and the circulation flow path 222 to the water storage tank 256. It was set on the circulation flow path 222 that only allows flow.

  Further, when the user sets the set temperature of hot water supply higher than the hot water storage upper limit value of the hot water storage tank 150, the heat treatment is always performed in the hot water heater 158. Therefore, in order to avoid a decrease in heat dissipation efficiency in an emergency such as a power outage and suppress unnecessary power consumption, the temperature setting is forcibly limited to the hot water storage upper limit value or changed to a temperature lower than the hot water storage upper limit value. Can also be prompted to the user.

  Further, after the circulation valve 228 is closed and the water pump 226 is stopped according to the determination of the heating detector 240, when the temperature of the hot water storage tank 150 becomes sufficiently high, the circulation valve control unit 236 and the water pump control unit 234 circulate. Should be determined to resume immediately. Therefore, the circulation valve control unit 236 and the water pump control unit 234 repeatedly execute the open / close determination of the circulation valve 228 and the drive determination of the water pump 226 every predetermined time, for example, every 1 to 10 minutes.

  However, the auxiliary control unit 230 opens the circulation valve 228 for a predetermined time, for example, 20 minutes after the power failure detection unit 224 detects the power failure, regardless of the water temperature of the hot water tank 150 or the determination of the heating detector 240. Subsequently, the water pump 226 is driven to circulate hot water. The predetermined time may be measured by the actual elapsed time, or by other parameters such as when a flow rate of 20 liters of hot water is detected by a flow rate sensor (not shown) provided in the circulation flow path 222. It can also be measured.

  As described above, even if the circulation valve control unit 236 closes the circulation valve 228 and stops the circulation of hot water, power generation is continued if the hot water in the hot water storage tank 150 does not reach the hot water storage upper limit value. However, under a predetermined condition such as when power generation is not performed for a long time, the temperature in the hot water storage tank 150 becomes uniform, and the temperature of the hot water on the vertical upper end side 170 of the hot water storage tank 150 is heated in the hot water heater 158. The temperature of hot water at the vertical lower end 172 may approach the hot water storage upper limit value. In this case, if power generation is performed without executing the circulation according to the present embodiment, the water temperature on the vertical lower end side 172 of the hot water storage tank 150 easily reaches the hot water storage upper limit value, and power generation may stop. Therefore, when the power failure detection unit 224 detects a power failure, the auxiliary control unit 230 forcibly circulates the hot water for a predetermined time regardless of the operation of the water heater 158 to temporarily lower the water temperature of the hot water tank 150 and continuously. Power generation is possible.

  Hot water supply valve 242 is provided on the outlet side of hot water heater 158, and opens and closes the flow path to hot water supply valve 176 in accordance with an instruction from valve control unit 232.

  The circulation radiator 246 cools the hot water sent from the hot water storage tank 150 to the circulation flow path 222. Such hot water cooling methods, like the power generator radiator 152, include a liquid cooling method using a liquid as a heat exchange medium and an air cooling method using air. In addition, the circulation radiator 246 is drained from the internal circulation passage 222 when not in use to prevent freezing.

  As described above, in the auxiliary unit 220, the hot water in the hot water storage tank 150 is radiated and circulated to continuously generate the power generation unit 110. However, if the water temperature decrease due to heat radiation is not in time for the water temperature increase in the hot water storage tank 150 due to power generation, the power generation of the power generation unit 110 may be interrupted. Here, by using the circulation radiator 246 to enhance the heat dissipation effect (cooling effect) of the hot water storage tank 150, stable power generation by the power generation unit 110 is possible.

  The circulation intake valves 248a and 248b are provided upstream and downstream of the circulation radiator 246, respectively, and intake air when the circulation radiator 246 is drained. Since the above-described circulation radiator 246 is also provided with a water suction inlet and a water drain valve in parallel, drainage is possible in conjunction with the circulation suction valves 248a and 248b.

  The drain valve 250 opens and closes the flow path of the water from the circulation radiator 246 when draining the circulation radiator 246.

  The drainage check valve 252 allows hot water sent from the circulation radiator 246 to flow and prevents backflow to the circulation radiator 246.

  The circulation check valve 254 allows hot water flowing out from the circulation radiator 246 to flow and prevents back flow to the circulation radiator 246 when hot water is circulated through the circulation passage 222 in an emergency such as a power failure.

  The water storage tank 256 is formed of a container having a heat radiation function such as metal capable of storing a predetermined volume (for example, 100 liters) of hot water and functions as a part of the circulation flow path 222.

  The water discharge / drain valve 258 opens and closes the circulation channel 222, in particular, the channel for draining hot water in the water storage tank 256 in accordance with the control of the drain valve control unit 238.

  The drain valve control unit 238 opens the water discharge / drain valve 258 and drains hot water from the water storage tank 256 when a temperature detected by a temperature detector 262 described later reaches a predetermined temperature or higher. The predetermined temperature is a temperature at which the water temperature of the hot water storage tank 150 is determined to reach the hot water storage upper limit value that stops power generation even if the hot water of the water storage tank 256 is sent to the hot water storage tank 150.

  The auxiliary unit 220 radiates and circulates the hot water in the hot water storage tank 150 so that the power generation unit 110 can continuously generate power. However, if the water temperature in the circulation channel 222 rises, the water temperature in the hot water storage tank 150 cannot be lowered sufficiently, and the power generation of the power generation unit 110 may be interrupted. Here, the hot water in the circulation channel 222 that has become a predetermined temperature or higher is drained and the low-temperature tap water is received, so that the heat dissipation effect (cooling effect) of the hot water storage tank 150 is enhanced and stable power generation by the power generation unit 110 is achieved. It becomes possible.

  The water discharge valve 260 opens and closes a flow path for discharging hot water or tap water accumulated in the water storage tank 256 to the outside. Similar to the power outage described above, a water outage can occur during a disaster. Here, the water circulating through the auxiliary unit 220 is stored in the water storage tank 256 and effectively used not only as a heat radiating medium but also as water used in the event of a water outage, thereby realizing both power supply and water supply functions. .

  However, the above-mentioned circulation radiator 246 is not filled with water in order to prevent freezing in a normal time other than an emergency such as a power failure. Therefore, when an emergency occurs, the circulation radiator 246 must first be filled with water. Therefore, the water discharge through the water discharge valve 260 is executed so as to leave at least the capacity to be charged in the circulation radiator 246.

  The temperature detector 262 is composed of a thermostat or the like, and is provided in the vicinity of the vertical lower end 184 of the water storage tank 256 in the circulation flow path 222, for example, and detects the water temperature in the water storage tank 256.

  The drainage drain valve 264 opens and closes the circulation channel 222, in particular, the channel for draining hot water in the water storage tank 256 in accordance with the control of the valve control unit 232.

  The flow sensor 266 is disposed downstream of the drainage drain valve 264 and upstream of the drainage check valve 268 and measures the flow rate of water flowing through the drainage drain valve 264.

  When the drain valve control unit 238 drains the hot water in the circulation channel 222, the drain check valve 268 allows the hot water sent from the drain drain valve 264 to flow and prevents a reverse flow to the drain drain valve 264.

  When the drainage water intake valve 270 discharges water through the water discharge valve 260, the exhaust water intake valve 270 takes in air corresponding to the amount of water discharged from the water discharge valve 260.

  The water supply valve 272 opens and closes the flow path from the water supply 182 to the water storage tank 256.

The water receiving pressure reducing valve 274 is connected to the water receiving valve 272, and reduces the water pressure to a predetermined value, for example, 3.7 kgf / cm ² to make the fluctuation uniform. The hot water storage tank 150 is provided with a tap water receiving port 174 for replenishing hot water supplied by the hot water heater 158. Therefore, in the present embodiment, the configuration of the existing water receiving port 174 is effectively used, and the tap water depressurized by the hot water radiated in the circulation flow path 222 and the water receiving pressure reducing valve 274 without altering the power generation unit 110. In addition, it is desirable to feed the water to the water receiving port 174.

  The water pressure sensor 276 is provided downstream of the water tap valve 272 and measures the water pressure.

  Based on the measurement result of the water pressure sensor 276, the water break detection unit 278 detects whether or not the water break is present.

  The tap water check valve 284 allows tap water to flow and prevents back flow from the water storage tank 256 to the tap water.

In addition, the water pump control unit 234 controls the water pump 226 so as to maintain the water pressure when the water cutoff detection unit 278 detects water cutoff (hereinafter simply referred to as “water cutoff”). The power generation unit 110 generates electrical energy and thermal energy as described above, and the generated thermal energy is replaced with hot water and accumulated in the hot water storage tank 150. However, if the supply of tap water to the hot water storage tank 150 is stopped due to water outage, hot water for recovering the heat generated during power generation cannot be secured. Therefore, the power generation control unit 160 of the power generation unit 110 has a hot water storage tank. When the measured value of the 150 water pressure sensors 180 becomes less than a predetermined pressure (for example, 0.5 kgf / cm ² ), the power generation by the fuel cell 154 is stopped, and the power generation is not resumed until the water cut-off is recovered and the predetermined recovery operation is performed. It is configured as follows. Here, the water pressure is maintained at a predetermined pressure or higher, and the hot water in the water storage tank 256 is supplied to the hot water storage tank 150 through the water supply pump 226 controlled by the water supply pump control unit 234. However, it is possible to generate power continuously.

  The water supply check valve 286 allows the water sent from the water pump 226 to flow and prevents the reverse flow to the water pump 226.

  Water supply valve 288 opens and closes the flow path from water supply check valve 286 to hot water storage tank 150 and water heater 158.

(Power generation method)
Next, a detailed processing flow of the power generation method in the power generation system 200 described above will be described. FIG. 3 is a state transition diagram showing state transition in the power generation method. As shown in FIG. 3, the power generation method transitions between four states: a normal state, a power outage state, a water outage state, and a power outage / water outage state. Here, first, the operation of each valve and pump of the power generation system 200 in four states will be described.

(Normal state)
FIG. 4 is an explanatory diagram showing the operation of each valve and pump in the normal state, and FIG. 5 is a schematic diagram for explaining the flow of hot water in the normal state. Each valve in the power generation system 200 is prepared with two valves, a valve that is open when not energized and a valve that is closed. Such energized / non-energized states are represented by ON / OFF in parentheses in the figure.

  As shown in FIG. 4, in the normal state, the pressure of the water supply 182 is normal, and the flow of hot water as shown by the thick line in FIG. The Accordingly, the hot water supply valve 242 of the hot water heater 158 is also opened so that the hot water heater 158 can supply hot water. Further, the drainage drain valve 264, the drainage drain valve 258, the circulation valve 228, and the drain valve 250 are closed (S1). In the normal state, since the circulation of hot water is not yet started, the water supply pump 226 is turned off, but the flow path is open, so that the tap water is supplied only by the water pressure flowing through the water supply pump 226. Water is sent to. At this time, if hot water is used in the water heater 158, the amount of water used is replenished from the water supply 182 and temporarily when the water temperature in the hot water tank 150 decreases due to water supply and water reception through the hot water supply. Power generation by the fuel cell 154 is resumed.

(Power failure state)
FIG. 6 is an explanatory diagram showing the operation of each valve and pump in the power failure state, and FIG. 7 is a schematic diagram for explaining the flow of hot water in the power failure state. In the event of a power failure, the hot water in the hot water storage tank 150 is circulated. Therefore, the circulation valve 228 is basically opened to secure a flow path between the hot water storage tank 150 and the circulation flow path 222, and a water supply pump 226 for circulating hot water. Is driven (S1).

  Here, when the heat detector 240 installed in the water heater 158 determines that the heat treatment is being performed, the circulation valve control unit 236 closes the circulation valve 228 and temporarily stops the circulation to stop the circulation. The water pump 226 is turned off through the controller 234 (S2). Then, when a predetermined time has elapsed, the water pump 226 is turned on again, the circulation valve 228 is opened, the circulation is restarted, and the presence or absence of the heat treatment is asked. With reference to the determination result of the heating detector 240, if the heating process is not performed, the opening state is maintained and the circulation is continued (S1). Here, a configuration is described in which the circulation valve 228 is closed when the circulation is stopped. However, when the water supply pump 226 is stopped, the flow of hot water almost disappears, and the circulation valve 228 can be left open. In the present embodiment, the circulation is stopped when the water temperature in the hot water storage tank 150 is low. In addition, when the circulation is continuously performed for a predetermined time, the circulation is temporarily stopped and the hot water storage is performed. You may comprise so that a circulation may be restarted when the inside of the tank 150 becomes high temperature or after fixed time progress.

  When the temperature detector 262 determines that the water temperature of the vertical lower end 184 of the water storage tank 256 is equal to or higher than the predetermined temperature when returning to the basic state (S1), the drain valve control unit 238 Regardless of whether or not the water cutoff detector 278 has detected no water cutoff, the water discharge / drain valve 258 is opened and the hot water in the water storage tank 256 is drained (S3). The drained hot water is replenished from the water supply 182. When a predetermined time has elapsed, the water discharge / drain valve 258 is closed to stop the drainage (S1). Here, the hot water of the water storage tank 256 that has become a predetermined temperature or higher is drained and the low-temperature tap water is received, so that the heat dissipation effect (cooling effect) of the hot water storage tank 150 is enhanced and power generation by the power generation unit 110 can be continued. Yes.

(Water outage)
FIG. 8 is an explanatory diagram showing the operation of each valve and pump in the water-stopped state, and FIG. 9 is a schematic diagram for explaining the flow of hot water in the water-stopped state. In the water cut-off state, the pressure of the water supply 182 decreases, and the power failure detection unit 224 does not detect a power failure, so the pressure of the water supply pump 226 is not applied. Therefore, if hot water supply by the water heater 158 is enabled, the pressure of the hot water in the hot water storage tank 150 decreases, the power generation unit 110 becomes abnormal in water shut-off, and power generation cannot be resumed when a power failure occurs later. Here, the hot water supply valve 242 is closed as shown in FIG. 8 (S1), and the hot water supply is restricted by limiting the hot water supply as shown in FIG. It can be avoided.

(Power failure / water outage)
FIG. 10 is an explanatory diagram showing the operation of each valve and pump in a power failure / water cutoff state, and FIG. 11 is a schematic diagram for explaining the flow of hot water in a power failure / water cutoff state. Even in the event of a power outage and water outage, the hot water in the water storage tank 256 is circulated in the same manner as the power outage. The water pump 226 is driven (S1).

  Here, when the heat detector 240 installed in the water heater 158 determines that the heat treatment is being performed, the circulation valve control unit 236 closes the circulation valve 228 in order to temporarily stop the circulation as in the case of a power failure. At the same time, the water pump 226 is turned off through the water pump controller 234 (S2). Then, when a predetermined time has elapsed, the water pump 226 is turned on again, the circulation valve 228 is opened, the circulation is restarted, and the presence or absence of the heat treatment is asked. With reference to the determination result of the heating detector 240, if the heating process is not performed, the opening state is maintained and the circulation is continued (S1). Here, when the heat treatment is being performed, the hot water in the hot water storage tank 150 is not circulated unnecessarily and is circulated only at a high temperature, so that a reduction in heat dissipation efficiency can be avoided and power consumption can be reduced.

  Also, unlike the water shutoff state, the water pump 226 is driven, and the pressure to the hot water storage tank 150 is maintained regardless of the decrease in the water pressure. Is also possible. Although the hot water supply valve 242 is closed in FIG. 10, when hot water supply is performed, the hot water supply valve 242 is temporarily opened until the amount of water in the water storage tank 256 becomes equal to or less than a predetermined amount of water.

  Subsequently, the state transition in FIG. 1. During a power failure 2. When power is restored 3. When water is shut off 4. At the time of condensing 5. When there is a water outage during a power outage 6. When condensing during a power outage, 7. During a power outage during a water outage, The explanation will be divided into 8 events when power is restored during a power outage. In addition, each predetermined time used in the following description refers to a time arbitrarily set based on a delay until each operation is completed.

(1. Power failure)
FIG. 12 is an explanatory diagram showing transition of opening and closing of each valve and pump in each process during a power failure. In the normal state, all the valves and pumps are OFF (S1), but when the power failure detection unit 224 detects a power failure, the water pump 226 is driven and the circulation valve 228 is opened, as shown in FIG. Operation in a power failure state is started (S2).

(2. When power is restored)
FIG. 13 is an explanatory diagram showing transition of opening and closing of each valve and pump in each process during power recovery. In the power failure state, the water discharge / drain valve 258 is basically closed, the circulation valve 228 is opened, and the water pump 226 is turned on. However, as described with reference to FIG. 6, the heat treatment unit 178 and the water tank 256 Depending on the water temperature of the vertical lower end 184, opening / closing and ON / OFF may be changed (S1). At this time, when power is restored, that is, when the power failure detection unit 224 does not detect the power failure, the water discharge / drain valve 258 and the circulation valve 228 are closed (S2). Then, the water drain valve 250 is opened to drain the water filled in the circulation radiator 246 (S3). After a predetermined time has elapsed, the water drain valve 250 is closed to finish draining the circulation radiator 246, and then the water pump 226 is stopped (S4). Thus, as shown in FIG. 4, the normal operation is started.

(3. When water is shut off)
FIG. 14 is an explanatory diagram showing transition of opening and closing of each valve and pump in each process at the time of water interruption. In the normal state, all the valves and pumps are OFF (S1), but when the water cutoff detector 278 detects water cutoff, the hot water supply valve 242 is closed (S2).

  Further, when the water break is detected but the power failure is not detected, it is not necessary to continue the power generation. Therefore, the circulation valve 228 is closed and the water pump 226 is also kept off. Thereby, the water pressure applied to the hot water storage tank 150 can be maintained in a normal state, and power generation can be started smoothly when a power failure occurs.

  At this time, the user can receive water from the water storage tank 256 by manually opening the water discharge valve 260 as necessary. However, as described above, since the water is not filled in the circulation radiator 246 at the time of non-circulation, water is stored so that only water (for example, 20 liters) to be filled in the circulation radiator 246 remains in the water tank 256 at the time of power failure. The extraction position of the water discharge valve 260 with respect to the tank 256 is adjusted. In addition, it is preferable that the water discharge valve 260 can be manually opened only when the water is shut off and cannot be taken when the water is not shut off. In this way, the operation in the water cut-off state is started as shown in FIG.

(4. Condensate)
FIG. 15 is an explanatory view showing the opening / closing transition of each valve and pump in each process during condensate. In the water shut-off state, the hot water supply valve 242 is closed (S1). Here, when the water cutoff detection unit 278 no longer detects water cutoff and the water pressure returns, the drainage drain valve 264 is first opened to receive water from the tap 182 and the air in the storage tank 256 through the drainage drain valve 264. Discharge (S2). When a predetermined flow rate is detected by the flow rate sensor 266, the drainage drain valve 264 is closed and the hot water supply valve 242 is opened (S3). Thus, the normal state as shown in FIG. 4 is restored, and the user can supply hot water.

(5. When there is a water outage during a power failure)
FIG. 16 is an explanatory diagram showing transition of opening and closing of each valve and pump in each process during a water outage during a power failure. In the power failure state, the water discharge / drain valve 258 is basically closed, the circulation valve 228 is opened, and the water pump 226 is turned on. However, depending on the water temperature of the heat treatment unit 178 and the vertical lower end 184 of the water storage tank 256, Or ON / OFF may have changed (S1). At this time, when the water cutoff detection unit 278 detects water cutoff, the drain valve control unit 238 is invalidated to close the water discharge / drain valve 258 and the hot water supply valve 242 in order to avoid draining water (S2). At this time, since the waste water storage intake valve 270 is opened, the user can manually open the water discharge valve 260 and receive hot water from the water storage tank 256 when necessary. In this way, as shown in FIG.

  Here, power generation is continued while preventing hot water from being discharged, and even if the temperature detector 262 detects an excess of a predetermined temperature, it is circulated by natural heat dissipation (for example, temporary stop of power generation) without depending on drainage. To maintain. Here, the drain valve control unit 238 is invalidated. However, even when power is cut off, power generation can be continued even if water is drained when power generation is given the highest priority.

(6. Condensation during a power outage)
FIG. 17 is an explanatory diagram showing the opening / closing transition of each valve and pump in each process during condensate during a power outage. When the water discharge detection valve 258 stops detecting water stoppage in the state where the water discharge / drain valve 258 is closed (S1), the water discharge / drain valve 264 is opened, and tap water is received by the water storage tank 256 and the water discharge / drain valve is opened. The air in the water storage tank 256 is exhausted from H.264 (S2). When a predetermined flow rate is detected by the flow sensor 266, the drainage drain valve 264 is closed, the invalidation of the drain valve control unit 238 is canceled, and the hot water supply valve 242 is opened to enable hot water supply (S3). Thus, the operation in the power failure state shown in FIG. 6 is started.

(7. During power outages during water outages)
FIG. 18 is an explanatory diagram showing transition of opening and closing of each valve and pump in each process during a power failure during a water outage. In the water shut-off state, the hot water supply valve 242 is closed (S1). When the power failure detection unit 224 detects a power failure during the water interruption, the circulation valve 228 is opened and the water pump 226 is driven. At this time, the water discharge / drain valve 258 is kept closed (S2). In this way, the operation in the power failure / water cutoff state as shown in FIG. 10 is started.

(8. When power is restored during a power outage)
FIG. 19 is an explanatory diagram showing the opening / closing transition of each valve and pump in each process during power recovery during a power outage. In the power failure state, the circulation valve 228 is basically open and the water pump 226 is turned on. However, depending on the heat treatment unit 178, opening / closing and ON / OFF may be changed (S1). If the power failure detection unit 224 stops detecting a power failure during a power failure, the circulation valve 228 is closed to stop the circulation (S2). Then, the water drain valve 250 is opened to drain the water filled in the circulation radiator 246 (S3). After a predetermined time has elapsed, the water drain valve 250 is closed to finish draining the circulation radiator 246, the hot water supply valve 242 is closed, and the water feed pump 226 is stopped (S4). In this way, the operation in a water shut-off state as shown in FIG. 8 is started.

  Even in such a power generation method, it is possible to continuously generate power during an emergency such as a power failure, thereby improving the convenience of the user and ensuring safety.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  It should be noted that each step in the above-described processing operation including the power generation method of the present specification does not necessarily have to be processed in time series according to the order described as an explanatory diagram, and may include processing in parallel or by a subroutine. Good.

  The present invention can be used for a power generation system that generates electric energy and thermal energy through a fuel cell, and an auxiliary unit.

DESCRIPTION OF SYMBOLS 100, 200 ... Power generation system 110 ... Power generation unit 120, 220 ... Auxiliary unit 150 ... Hot water storage tank 154 ... Fuel cell 156 ... Heat exchanger 158 ... Water heater 160 ... Power generation control part 178 ... Heat processing part 222 ... Circulation flow path 224 ... Power failure detection unit 226 ... Water pump 228 ... Circulation valve 236 ... Circulation valve control unit 238 ... Drain valve control unit 240 ... Heating detector 256 ... Water tank 262 ... Temperature detector 278 ... Water cut detection unit

Claims (5)

A power generation system including a power generation unit and an auxiliary unit connected to the power generation unit,
The power generation unit is
A hot water tank for storing hot water and keeping warm,
A fuel cell that generates electrical and thermal energy through chemical reactions;
A heat exchanger that recovers the generated thermal energy by heat exchange with hot water in the hot water tank;
A power generation control unit that drives the fuel cell to generate power when the hot water in the hot water tank is lower than a predetermined temperature, and stops power generation by the fuel cell when the temperature is equal to or higher than the predetermined temperature;
With
The auxiliary unit is
A circulation channel for radiating hot water passed from the hot water tank;
Determining whether the hot water in the hot water tank is high temperature or low temperature, circulating the hot water in the hot water tank to the circulation channel when the temperature is high, and stopping the circulation when the temperature is low;
A power generation system comprising: A hot water storage tank for hot water hot water storage and thermal insulation, and a fuel cell for generating electrical energy and thermal energy through a chemical reaction, a heat exchanger for recovering heat energy which is the product by heat exchange with the hot water該貯tundish, the An auxiliary unit connected to a power generation unit including a power generation control unit that drives the fuel cell to generate power when the hot water in the hot water tank is lower than a predetermined temperature, and stops power generation by the fuel cell when the temperature exceeds the predetermined temperature. There,
A circulation channel for radiating hot water passed from the hot water tank;
An auxiliary control unit that determines whether the hot water in the hot water tank is hot or cold, circulates the hot water in the hot water tank in the circulation channel when the temperature is high, and stops the circulation when the temperature is low;
An auxiliary unit comprising: A power failure detection unit that detects power failure is further provided.
The auxiliary unit according to claim 2, wherein the auxiliary control unit circulates the hot water when the power failure detection unit detects a power failure and the hot water in the hot water tank is hot.   4. The auxiliary unit according to claim 3, wherein the auxiliary control unit circulates the hot water for a predetermined time after the power failure detection unit detects a power failure regardless of the temperature of the hot water in the hot water tank. The circulation channel receives hot water from the hot water tank through a water heater that supplies hot water from the hot water tank,
A heating detector for detecting whether heat treatment is performed in the water heater;
The auxiliary control unit determines that the water temperature of the hot water tank is low when the heating detector detects that the heat treatment is being performed. The auxiliary unit according to item 1.

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